Iraq's information minister shows what he says are the remains of a coalition missile

It said precision-guided weapons were used to target Iraqi missiles and launchers on Wednesday.

A statement issued by the Qatar-based HQ said the Iraqi missiles were hidden in a residential area less than 100 metres (300 feet) from homes.

Iraqi officials say at least 14 people were killed and 30 injured in explosions in the busy Shaab district of northern Baghdad during an air raid.

But the situation is still confused - with a later Pentagon briefing saying it is still not clear what caused the blasts in Shaab.

Key military developments

• A column of up to 1,000 Iraqi Republican Guard vehicles is reported to be heading south from Baghdad towards Najaf. A Western journalist attached to the US Seventh Cavalry says the column is moving very close to the US units, but a continuing sandstorm in the area has grounded US helicopters

• Several hundred troops from the US Army's 173rd Airborne Brigade parachute into northern Iraq and seize a key airfield, a US defence official says

• Coalition warplanes attack a huge convoy of tanks and armoured personnel carriers which was heading south-east from Basra towards the al-Faw peninsula

• Republican Guard units in the outskirts of Baghdad continue to be bombed

• Coalition forces fire intense artillery barrages towards the city of Nasiriya - about 370 kilometres (230 miles) south-east of Baghdad

IRAQ CAMPAIGN Map: Military operations Iraq's Republican Guard

The Pentagon said coalition forces did not target a marketplace in Baghdad nor were any bombs or missiles dropped or fired in the district where the explosions happened.

Pentagon spokesman Major General Stanley McChrystal said: "We don't know for a fact whether it was US or Iraqi. And we can't make any assumption on either at this point.

"Another explanation could be that (Iraqi) triple-A [anti-aircraft artillery] or surface-to-air missile that missed its target fell back into the marketplace area."

If the Shaab explosion is proved to be caused by a coalition attack, correspondents say it will be a blow to attempts by the US-led forces to minimise civilian casualties during their drive to unseat Iraqi leader Saddam Hussein.

But heavy bombing of the Iraqi capital continued throughout Wednesday with three huge explosions rocking Baghdad in the late evening.

And 20 US Marines are reported to have been injured on Wednesday evening when Iraqi forces launched rocket attacks on their positions south of Nasiriya.

There was also more fighting near Basra on Wednesday afternoon when coalition warplanes attacked a huge convoy of tanks and armoured personnel carriers which headed south-east towards the al-Faw peninsula.

British radar spotted the column of between 70 and 120 vehicles following the coast road along the Shatt al-Arab waterway and a number of fighter jets were scrambled to engage the column.

BBC correspondent Clive Myrie is close to the area and says the movement of Iraqi armour may be a counter-attack to recapture ground lost over the last two or three days, or possibly a tactical retreat from Basra because of the possibility of an uprising in the north of the city.

British troops are positioned along the coast road as well as around Basra.

The reports of an uprising in the city have been dismissed by the Iraqis.

In other developments: